From: Zach Brown Subject: Re: [RFC/PATCH 0/2] ext4: Transparent Decompression Support Date: Thu, 25 Jul 2013 13:09:39 -0700 Message-ID: <20130725200939.GH26554@lenny.home.zabbo.net> References: <1374699833.7083.2.camel@localhost> <20130724233628.GD3641@logfs.org> <51F14136.30409@mozilla.com> <20130725180545.GB15590@logfs.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Dhaval Giani , linux-kernel@vger.kernel.org, tytso@mit.edu, tglek@mozilla.com, vdjeric@mozilla.com, glandium@mozilla.com, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org To: =?iso-8859-1?Q?J=F6rn?= Engel Return-path: Received: from mx1.redhat.com ([209.132.183.28]:18570 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756465Ab3GYUJp (ORCPT ); Thu, 25 Jul 2013 16:09:45 -0400 Content-Disposition: inline In-Reply-To: <20130725180545.GB15590@logfs.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: > > What about introducing a new flag, O_COMPR which tells the > > kernel, btw, we want this file to be decompressed if it can be. It > > can fallback to O_RDONLY or something like that? That gets rid of > > the chattr ugliness. > > How is that different from chattr ugliness, which also comes down to a > single flag? ;) It's much worse because it's per fd instead of per inode. The page cache, where the undisclosed complexity of this proposal lurks, where compressed and uncompressed cached copies of the data need to be managed somehow, is per inode. - z (Hi Taras! :))